AQA GCSE Combined Science: Trilogy Biology Paper 1 (Higher), June 2025: Question 1

10 marks · Low Demand difficulty · Short Answer

Identify structures and functions of the heart, explain the presence of mitochondria in heart muscle cells, and suggest symptoms and surgical risks related to a hole in the heart.

Practise this question

Question

Question 1 includes two diagrams of the heart. Figure 1 shows a schematic model with labeled chambers C, D, E, F and blood vessels A and B, indicating direction of blood flow. Part 01.1 asks students to match blood vessels A and B to their names: Aorta, Pulmonary artery, Pulmonary vein, Vena cava. Part 01.2 asks where the natural pacemaker is located among C, D, E, and F. Part 01.3 asks to explain why heart muscle cells contain many mitochondria. Figure 2 shows an anatomical diagram of a heart highlighting the position of a 'hole in the heart' in the septum between the ventricles. Part 01.4 asks to suggest two symptoms of a hole in the heart. Part 01.5 describes an operation using a flexible tube and mesh patch to repair the hole, asking for two possible risks of the operation.
Question text

01 The heart is an organ that pumps blood around the body.

Figure 1 is a model of the heart and shows the direction of blood flow.

Figure 1

01.1 Draw one line from each blood vessel shown in Figure 1 to the name of the

blood vessel.

[2 marks]

01.2 Heart rate is controlled by a group of cells.

The group of cells acts as a pacemaker.

Where would the pacemaker be located in Figure 1?

[1 mark]

*02Tick (* ) one box.

C D E F

01.3 Heart muscle cells contain many mitochondria.

Explain why heart muscle cells contain many mitochondria.

[3 marks]

A small number of people are born with a ‘hole in the heart’.

Figure 2 shows the position of a hole in the heart.

Figure 2

01.4 The hole allows some blood from the right side of the heart to mix with blood in the left

side of the heart.

Suggest two symptoms of having a hole in the heart.

[2 marks]

01.5 In an operation to repair a hole in the heart:

• a flexible tube is inserted into a blood vessel and guided to the heart

• a mesh patch is passed down the tube

• the mesh patch covers the hole.

Heart tissue grows around the mesh and closes the hole.

Suggest two possible risks of this operation to repair a hole in the heart.

[2 marks]

Mark scheme

Show the mark scheme Mark scheme for Question 1: 01.1 links vessel A to Vena cava (1 mark) and vessel B to Aorta (1 mark). 01.2 gives 1 mark for box F. 01.3 awards up to 3 marks for: (more) respiration in mitochondria, releases more energy, so the heart muscle contracts. 01.4 gives 2 marks for any two symptoms from: fast/increased heart rate, fast/increased breathing rate, tiredness/fatigue, pale/blue/cold skin, heart attack, difficulty exercising, or difficulty gaining weight. 01.5 gives 2 marks for any two surgical risks from: heavy/internal bleeding, infection, damaging blood vessels, damaging the heart, risk from anaesthetic, or risk of rejection.

Question 1

AO /

Question Answers Mark

Spec. Ref.

01.1 AO1

4.2.2.2

do not accept more than one line from a box on the left

AO /

Question Answers Extra information Mark

Spec. Ref.

01.2 F 1 AO1

4.2.2.2

AO /

Spec. Ref.

01.3 1 AO2

(more) respiration (in do not accept anaerobic

mitochondria) respiration

(which) releases more energy allow (muscles) need more 1 AO2

energy

do not accept energy produced

/ made / created

do not accept provides more

energy for respiration

(so the heart) muscle contracts 1 AO1

4.2.2.2

4.4.2.1

4.1.1.2

AO /

Spec. Ref.

01.4 any two from: 2 AO3

4.2.2.2

• fast / increased heart rate allow irregular heartbeat

• fast / increased breathing ignore shortness of breath

(rate)

• tiredness allow fatigue

• pale skin allow blue skin (due to poor

oxygenation)

allow cold / cool skin (to the

touch)

allow cyanosis

• heart attack allow blood clots

allow chest pain

allow stroke

• difficulty exercising

• difficulty gaining weight

allow increased sweating

allow frequent chest infections

allow swelling in legs / feet /

abdomen

AO /

Spec. Ref.

01.5 any two from: 2 AO3

4.2.2.2

• heavy / internal bleeding

• infection allow named infection e.g.

MRSA

ignore risk of disease

• damaging blood vessels

• damaging the heart allow blood clots

allow stroke

allow heart attack

allow irregular heartbeat

• risk from anaesthetic

• risk of rejection (of the mesh /

tube)

ignore damage unqualified

Total Question 1 10

How to answer it

The Heart: Anatomy, Function & Medical Conditions

📋 What this question tests

This question assesses your understanding of the circulatory system: identifying major blood vessels and chambers of the heart, recalling the function and location of the natural pacemaker, explaining cellular respiration in cardiac muscle cells, and applying biological knowledge to real-world medical conditions ("hole in the heart" and surgical interventions).

Part 01.1: Identifying Blood Vessels

Matching vessels A and B to their correct scientific names [2 marks]

✅ Correct Answer

  • A connects to Vena cava
  • B connects to Aorta
Award 1 mark for each correctly drawn line. If more than one line is drawn from box A or box B, zero marks are awarded for that vessel.

💡 Key Knowledge

  • Remember the orientation: The diagram is viewed as if looking at a patient's chest. The right side of the heart is on your left.
  • Vena cava: Brings deoxygenated blood from the body into the right atrium (F).
  • Aorta: Carries oxygenated blood at high pressure from the left ventricle (D) to the rest of the body.

Part 01.2: The Natural Pacemaker

Locating the pacemaker cells in the heart [1 mark]

✅ Correct Answer

Tick in box: F

1 mark for ticking box F only.

💡 Heart Chamber Guide

  • F = Right Atrium (receives blood from body)
  • E = Right Ventricle (pumps blood to lungs)
  • C = Left Atrium (receives blood from lungs)
  • D = Left Ventricle (pumps blood to body)
  • The natural pacemaker is a cluster of specialised electrical cells situated specifically in the wall of the right atrium.

❌ Common Misconception

Students frequently confuse the atria (top chambers) with the ventricles (bottom chambers), or pick C (left atrium) forgetting that the anatomical "right side" is shown on the left of the diagram.

Part 01.3: Mitochondria in Heart Muscle

Explaining why heart muscle cells contain many mitochondria [3 marks]

✅ Full Mark Response

  1. To carry out (aerobic) respiration [1 mark]
  2. To release energy [1 mark]
  3. So that heart muscle can contract / pump blood continuously [1 mark]

❌ Critical Examiner Traps

  • NEVER say "make", "create", or "produce" energy: Energy cannot be created. You will lose the mark unless you write "releases energy".
  • Do not write "anaerobic respiration": Heart muscle operates via continuous aerobic respiration.
  • Do not say "provides energy for respiration": Respiration is the process that releases energy, not consumes it!

🧠 Exam Technique: 3-Step Structure

Whenever an exam question links an organelle to cell function:
1. Name the process: Aerobic respiration.
2. State the biological output: Releases energy (from glucose).
3. State the cell's requirement: For continuous muscle contraction.

Part 01.4: Symptoms of a Hole in the Heart

Suggesting two symptoms when blood from both sides mixes [2 marks]

✅ Correct Answer (Any 2 of the following)

  • Tiredness / fatigue
  • Fast / increased heart rate (or irregular heartbeat)
  • Fast / increased breathing rate
  • Pale skin / blue skin (cyanosis) / cold skin
  • Difficulty exercising
  • Difficulty gaining weight (in babies/children)
  • Heart attack / chest pain
1 mark for each valid symptom (maximum 2 marks).

💡 The Biological Reason Why

When oxygenated blood (left side) and deoxygenated blood (right side) mix, the blood delivered to body tissues carries significantly less oxygen. As a result, cells cannot respire efficiently, causing fatigue, and the heart/lungs work harder (faster rate) to compensate.

❌ Common Errors

  • Examiners explicitly instructed: "ignore shortness of breath" (it is too vague; specify rapid / increased breathing rate instead).
  • Avoid generic, non-clinical answers like "feeling sick" or "pain" without specifying chest pain.

Part 01.5: Surgical Risks of Catheter Repair

Suggesting two possible risks of using a catheter mesh operation [2 marks]

✅ Correct Answer (Any 2 of the following)

  • Infection (e.g. bacterial infection / MRSA)
  • Heavy / internal bleeding
  • Damage to blood vessels
  • Damage to the heart (or blood clots / stroke / irregular heartbeat)
  • Risk from anaesthetic
  • Risk of rejection (reaction to foreign mesh/tube)
1 mark for each valid surgical risk (maximum 2 marks).

🧠 Exam Technique: Context-Specific Risks

This is an operational procedure involving passing a tube into blood vessels and leaving a foreign object (mesh patch) in the heart. Always think about the physical pathway:
• Entry point: bleeding, vessel damage.
• Sterility: infection.
• Foreign material: rejection, blood clotting.

❌ Insufficient Answers

  • Writing just "damage" without qualification receives 0 marks. You must state what is damaged (e.g. blood vessels or heart tissue).
  • Do not write "risk of disease" — write infection.

Topics

Biology · B2: Organisation · B1: Cell Biology · B4: Bioenergetics

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 1 (Higher), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.